It’s not organized at all but I just point RetroArch to a network share

I see, using “is” could be a downcast from any type. But from object it would always be an upcast so you don’t need an explicit casting operator

Your code does not follow the pattern matching syntax; I don’t see “is” anywhere. That’s what is actually doing the casting

Edit: I think I’m completely wrong about “is” being required

The “is” is a part of pattern matching which I don’t believe regular switches can do. Only switch expressions. The example in the link you gave is checking the type by casting using “is”.